feat: Enhance idea retrieval to include the latest generation and support user-specific ideas not tied to a project, while also improving asset storage uniqueness and adjusting generation cancellation timeout.

models/Idea.py

@@ -6,7 +6,7 @@ class Idea(BaseModel):
     id: Optional[str] = None
     name: str = "New Idea"
     description: Optional[str] = None
-    project_id: str
+    project_id: Optional[str] = None
     created_by: str  # User ID
     is_deleted: bool = False
     created_at: datetime = Field(default_factory=datetime.now)